What is my Rifle’s [Accurate] Barrel Life Expectancy?
With long range precision shooting becoming increasingly popular amongst rifle owners throughout the world, barrel life expectancy is often a question of concern, particularly amongst new buyers. A barrel’s life expectancy can vary vastly from one caliber to the next. So what is accurate barrel life, and how do we determine a barrel’s life expectancy?
Accurate barrel life can defined as the point where precision will start to decline. An occasional shooter may still enjoy years of successful shooting beyond this point, however precision will gradually decline, until eventually reaching a point where precision and accuracy is no longer satisfactory. A barrel’s life expectancy is caliber dependant, and may range anywhere from 1000 rounds to 6000 rounds or more.
While barrel life many not be financially concerning for many shooters around the world, it is still good to understand roughly how long your barrel may last until precision starts to decline. This will assist in understanding why groupings may eventually open up, while also allowing for timeous submission of new license applications in certain countries around the world; take South Africa for example, where a barrel may take up to 1-year to license.
Barrel Life Comparison Chart
The following chart displays accurate barrel life data for a number of popular rifle cartridges. This data may of course vary in reality (depending on a wide range of variables), but it will give you a good indication of which cartridges to stay away from if you plan on spending excessive amounts of time at the range, and are concerned over your barrel’s lifespan.
|Caliber||*Accurate Barrel Life||Rating|
|.308 Winchester||5000 Rounds||★★★|
|.223 Remington||4200 Rounds||★★★|
|6.5 Creedmoor||3800 Rounds||★★|
|.30-06 Springfield||3100 Rounds||★★|
|.243 Winchester||2800 Rounds||★★|
|.338 Lapua Magnum||1700 Rounds||★|
|.50 BMG||1500 Rounds||★|
|.270 Winchester||1400 Rounds||★|
|.300 Winchester Magnum||1350 Rounds||★|
These figures are intended for comparative purposes only and predicts target precision barrel life.
Determining Accurate Barrel Life
In order to determine the accurate barrel life of a rifle, we can use a barrel life calculator. The most widely used barrel life calculator on the web today is known as Mike’s Spreadsheet, which uses five variables to provide a good accurate barrel life estimation. These five variables are as follows:
- Bullet Diameter – the caliber of bullet being fired through your barrel.
- Powder Charge Weight – the amount of powder loaded into your cartridge.
- Powder Heat Potential – measured in kilojoules per kilogram (kJ/kg). Pierre Vanderwalt’s modified version of Mike’s Spreadsheet automatically provides some of the most common Powder Heat Potential figures for you. Mike’s Spreadsheet also provides a table with Heat Potential ratings for most popular powder types. Alternatively you can purchase and use QuickLoad to find this data.
- Pressure – measured in pounds per square inch (psi), this data can be estimated by purchasing and becoming familiar with QuickLoad ballistics software, or alternatively conducting a google search to try and find data that matches your cartridge load.
- Bullet Coating – simply select whether you are using moly-coated bullets or not. In most cases, the answer is “no” – unless you are using moly-coated bullets of course.
Why Do Rifle Barrels Wear Out?
Throat erosion is often the main determining factor of a rifle barrel’s life. The throat is the part of the barrel where the bullet exits the cartridge and begins the rifling process, or in simpler terms, where the rifling begins.
When the rifle is fired, the explosive heat and pressure from the propellant gasses begin to erode the throat of the barrel’s interior surface. This erosion is accelerated when cartridges are loaded hot (adding additional propellant) with the aim of increasing the bullet’s velocity.
A rifle barrel can continue wearing while still proving the shooter with many months or years of successful shooting, until reaching a point where the barrel no longer provides the accuracy that you require from the rifle. At this point we can say that it has reached the end of its barrel life, and seek a replacement.
As your barrel starts to reach the end of its accurate lifespan, you may notice that bullet seating depth gradually increases, while group sizes enlarge and precision degrades. This may continue until eventually the rifling is not longer able to stabilise the bullet, and you will notice sideways impacts of the bullet on targets at all distances, even those placed not far from the muzzle.
How do I Increase my Barrel’s Lifespan?
There are a number of things that a shooter can do to reduce barrel wear. One of the easiest ways is to select a cartridge load that does not necessarily produce the fastest muzzle velocity, but rather considers barrel life versus effective range and stopping power; settling on a favourable compromise.
Let’s use the following .300 Winchester Magnum loads to demonstrate. Note: the following data does not necessarily demonstrate the most accurate load (or node), but rather demonstrates how barrel wear can be reduced by altering the propellant load.
- Bullet: Hornady 195gr ELD Match
- Propellant Load: 75.5gr of Vihtavuori N560
- Muzzle Velocity: 3025fps
- Muzzle Energy: 3975ft-lbs
- Effective Range at Sea-Level Pressure: 1440 meters
- Accurate Barrel Life: 1003 Rounds
- Bullet: Hornady 195gr ELD Match
- Propellant Load: 75.5gr of Vihtavuori N165
- Muzzle Velocity: 2932fps
- Muzzle Energy: 3738ft-lbs
- Effective Range at Sea-Level Pressure: 1390 meters
- Accurate Barrel Life: 1895 Rounds
- Bullet: Hornady 195gr ELD Match
- Propellant Load: 70.5gr of Vihtavuori N165
- Muzzle Velocity: 2748fps
- Muzzle Energy: 3284ft-lbs
- Effective Range at Sea-Level Pressure: 1280 meters
- Accurate Barrel Life: 2705 Rounds
The above load results show us the following:
- Load #1 – this load uses a propellant known for producing high muzzle velocities, but is also sensitive to temperature changes. Shooters who want the fastest muzzle velocity and hardest hitting bullet may enjoy this load, but as we can see, accurate barrel life is poor at around 1000 rounds.
- Load #2 – changing propellant to a more consistent option but with slower velocities sacrifices only 50 meters (or 3.5%) in effective range, and 6% in muzzle energy. However, accurate barrel life increases by 89%, and temperature effects are more manageable.
- Load #3 – this load uses the same propellant as Load #2, but with 5.0grains less in propellant charge. Effective range has decreased by a further 8%, while muzzle energy has decreased by a further 12%, but accurate barrel life has increased by 170% when compared to Load #1.
Some other methods of increasing a barrel’s life and reducing throat erosion are as follows:
- Rotate between two or three rifles, thus spreading out the number of rounds fired through each barrel.
- Allow extra time for your barrel to cool between shots, and avoid rapid or sustained fire where possible.
- Ensure correct methods of cleaning and maintenance. Poor cleaning practices can reduce the life of a barrel by damaging rifling. But also don’t over-clean your rifle; only clean when necessary.
- You may wish to shoot moly-coated bullets to extend barrel life. Coated bullet benefits are hotly debated, so research this one thoroughly and proceed with caution if you decide to do so.
- And finally, as demonstrated by the example above, shoot less-powerful cartridges.
How do I Monitor my Barrel’s Life?
Barrel life is monitored by keeping a record of all shots fired through each barrel. This is known as a barrel log.
A barrel log should be kept for each rifle in your Shooting Record Book, or Field Data Book, and may also be stored on an electronic copy or cloud drive for safekeeping. For more information about keeping a Shooting Record Book, read our article titled: How to Estimate Range with the Mil-Dot Reticle (Subheading: How to Determine Target Size).
It should now be apparent that there is no easy answer to how many rounds a rifle barrel can fire before accuracy declines; there are simply too many variables involved. The answer also relies heavily on your goals; a benchrest shooter will consider a barrel shot-out long before a hunter will.
If barrel life is of a concern to you, use the advice given above on how to increase your barrel’s lifespan. But at the end of the day, a rifle is made to be enjoyed, so don’t hold back on shooting your rifle over concerns of losing accuracy, but rather enjoy the rifle and monitor barrel life so that you can prepare for a replacement when one is due.
If you enjoyed this article please leave a comment below, and keep an eye out for future posts.